ERBB2 and neoplasm: Adequate pathologic material for analyses is the key element of any quality-controlled laboratory procedure.11,12,21,26 Considering the heterogeneity in HER2 expression across tumour cells in GOC,14 a minimum of 5 biopsies are required according to literature data,12,13,21 with 6 to 8 specimens considered as the optimal threshold for adequate and reliable HER2 assessment in GOC by available recommendations.11 So, we set 6 as the reference number to categorise biopsy samples adequacy.